Description Time-Sert 4212H M12 x 1.25mm Metric Deep Hole Spark Plug Thread Repair Kit. Time Sert Deep Hole Spark Plug Thread Repair Kits Made in USA. Time Sert 4212H thread repair inserts. M12 x 1.25mm Deep Hole spark plug repair kit part no. 4212H tooling Click here: for video instructions  Order Washer Seat Inserts Click Here Get Useful Tools, Tap Guides, and More Click Here  Click Here For Instructions